Crothian is correct of course, in that "low magic" means different things to different people.
But sure, I can throw some names of games or supplements around, I guess:
A Game of Thrones (you did use the phrase "think Song of Ice and Fire", after all)
Artesia (nicely put together, and very cool - but not d20, if that matters)
Legends of Sorcery (this one allows easy customisation of magic to pretty much whatever level you want, in combination with standard d20 fantasy rules. . . if desired).
As previously mentioned, a fair few people use Iron Heroes, Grim Tales or Conan OGL for low magic d20.
Also as mentioned, True20 can do this. . . as it can do virtually anything. I recommend checking it out, for fantasy, S&S, modern, horror, sci-fi. . . whatever the genre, really. My bias here is that I'm currently running True20 and loving it, so please forgive my slight fanboyishness.
I'm another crazy person who's used (heavily) house-ruled D&D 3.5 for "low magic" campaigns - it's a lot of work, but yes, it can be done. I'm not sure if I would suggest doing this though, unless you
love D&D 3e, and
love the "low magic" thing, to the extent that you won't give up on either of them too readily.